1. Field of the Invention
The invention relates to a method of assembling together parts of different natures by diffusion welding, one of the parts being made of titanium and the other of steel, and it also relates to metal parts obtained by the method, in particular turbine shafts for turbomachines.
2. Description of the Related Art
In the context of research seeking to reduce the noise, the fuel consumption, and the CO2 emissions of airplane engines, the torque transmitted by the low-pressure turbine shaft of a turbomachine has been increased very significantly, but without changing the diameter and the weight of the shaft, thereby leading the Applicant to investigate making a shaft having a central portion of composite material with a titanium matrix and including end pieces made of high-strength steel, which end pieces can be machined to have shapes that are relatively complex for connection to other components of the turbomachine.
Assembling together the titanium central portion with the steel endpieces raises problems that have so far not yet been solved in satisfactory manner, particularly since the titanium-steel junctions need to present very strong mechanical characteristics for turbine shafts.